NZ used to be a 80-90%+ white country (with the other 10%-20% being Polynesian) until very recently. The overwhelming majority of the Asian population immigrated in recent decades, and it takes a some time for families to establish themselves in a new country in order to have the luxury of pursuing politics as a career. When Italians and Irishmen started immigrating to the USA, it took decades for them to build up the social networks and capital in order to climb to the ranks of Governors, Mayors, etc. too.